Cost-effectiveness of a screening strategy for Q fever among pregnant women in risk areas: a clustered randomized controlled trial

Janna M Munster,Josien Riphagen-Dalhuisen,Ronald P Stolk,Jamie Meekelenkamp,Lolkje Tw ,Alexander Cap Leenders,Carl Jcm Hamilton,Jerome R Lo-Ten-Foe,Wim Van Der Hoek,Albertus Timmer,Jan G Aarnoudse,Ariene Rietveld,Eelko Hak,Peter M Schneeberger,Esther De Vries

doi:10.1186/1472-6874-10-32

Abstract

BackgroundIn The Netherlands the largest human Q fever outbreak ever reported in the literature is currently ongoing with more than 2300 notified cases in 2009. Pregnant women are particularly at risk as Q fever during pregnancy may cause maternal and obstetric complications. Since the majority of infected pregnant women are asymptomatic, a screening strategy might be of great value to reduce Q fever related complications. We designed a trial to assess the (cost-)effectiveness of a screening program for Q fever in pregnant women living in risks areas in The Netherlands.Methods/designWe will conduct a clustered randomized controlled trial in which primary care midwife centres in Q fever risk areas are randomized to recruit pregnant women for either the control group or the intervention group. In both groups a blood sample is taken around 20 weeks postmenstrual age. In the intervention group, this sample is immediately analyzed by indirect immunofluorescence assay for detection of IgG and IgM antibodies using a sensitive cut-off level of 1:32. In case of an active Q fever infection, antibiotic treatment is recommended and serological follow up is performed. In the control group, serum is frozen for analysis after delivery. The primary endpoint is a maternal (chronic Q fever or reactivation) or obstetric complication (low birth weight, preterm delivery or fetal death) in Q fever positive women. Secondary aims pertain to the course of infection in pregnant women, diagnostic accuracy of laboratory tests used for screening, histo-pathological abnormalities of the placenta of Q fever positive women, side effects of therapy, and costs. The analysis will be according to the intention-to-screen principle, and cost-effectiveness analysis will be performed by comparing the direct and indirect costs between the intervention and control group.DiscussionWith this study we aim to provide insight into the balance of risks of undetected and detected Q fever during pregnancy.Trial registrationClinicalTrials.gov, protocol record NL30340.042.09.

Highlights

In The Netherlands the largest human Q fever outbreak ever reported in the literature is currently ongoing with more than 2300 notified cases in 2009
With this study we aim to provide insight into the balance of risks of undetected and detected Q fever during pregnancy
Q fever, a zoonosis caused by Coxiella burnetii (C. burnetii), primarily infects ruminants and rodents [1]

Summary

Introduction

In The Netherlands the largest human Q fever outbreak ever reported in the literature is currently ongoing with more than 2300 notified cases in 2009. Pregnant women are at risk as Q fever during pregnancy may cause maternal and obstetric complications. The organism spreads in 2300 cases in 2009 [3,4,5] This observation has led to several meetings of the Dutch Outbreak Management Team (OMT) of the Ministry of Health to curb the epidemic. In a Canadian cohort study in an affected area, 3.8% of parturient women had evidence of previous exposure to C. burnetii. These women had higher risks for adverse obstetrical outcome in terms of premature delivery and prior or current neonatal death [11]. Transmission across the placenta, transmission by inhalation of infected amniotic fluid or by ingestion of infected milk cannot be excluded

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